commit 767029e4d421e31185e215d22eb207d3bf7f5c22
Author:     Fabian Greffrath <fabian@greffrath.com>
AuthorDate: Sun Feb 5 00:15:56 2017 +0100
Commit:     Fabian Greffrath <fabian@greffrath.com>
CommitDate: Sun Feb 5 00:15:56 2017 +0100

    Add option to force integer scales for resolution-independent rendering

    Fixes #853
---
 src/i_video.c       | 11 +++++++++++
 src/i_video.h       |  1 +
 src/m_config.c      |  6 ++++++
 src/setup/display.c |  5 +++++
 4 files changed, 23 insertions(+)

diff --git a/src/i_video.c b/src/i_video.c
index 97f97d23..55a1f45f 100644
--- a/src/i_video.c
+++ b/src/i_video.c
@@ -122,6 +122,10 @@ int fullscreen = true;

 int aspect_ratio_correct = true;

+// Force integer scales for resolution-independent rendering
+
+int integer_scaling = false;
+
 // Force software rendering, for systems which lack effective hardware
 // acceleration

@@ -1151,6 +1155,12 @@ static void SetVideoMode(void)
                              SCREENWIDTH,
                              EffectiveScreenHeight());

+    // Force integer scales for resolution-independent rendering.
+
+#if SDL_VERSION_ATLEAST(2, 0, 5)
+    SDL_RenderSetIntegerScale(renderer, integer_scaling);
+#endif
+
     // Blank out the full screen area in case there is any junk in
     // the borders that won't otherwise be overwritten.

@@ -1330,6 +1340,7 @@ void I_BindVideoVariables(void)
     M_BindIntVariable("fullscreen",                &fullscreen);
     M_BindIntVariable("video_display",             &video_display);
     M_BindIntVariable("aspect_ratio_correct",      &aspect_ratio_correct);
+    M_BindIntVariable("integer_scaling",           &integer_scaling);
     M_BindIntVariable("startup_delay",             &startup_delay);
     M_BindIntVariable("fullscreen_width",          &fullscreen_width);
     M_BindIntVariable("fullscreen_height",         &fullscreen_height);
diff --git a/src/i_video.h b/src/i_video.h
index a4ac1a79..59125103 100644
--- a/src/i_video.h
+++ b/src/i_video.h
@@ -90,6 +90,7 @@ extern int screen_width;
 extern int screen_height;
 extern int fullscreen;
 extern int aspect_ratio_correct;
+extern int integer_scaling;
 extern int force_software_renderer;

 #endif
diff --git a/src/m_config.c b/src/m_config.c
index 718226bc..04c17cdb 100644
--- a/src/m_config.c
+++ b/src/m_config.c
@@ -727,6 +727,12 @@ static default_t extra_defaults_list[] =

     CONFIG_VARIABLE_INT(aspect_ratio_correct),

+    //!
+    // If non-zero, forces integer scales for resolution-independent rendering.
+    //
+
+    CONFIG_VARIABLE_INT(integer_scaling),
+
     //!
     // Window width when running in windowed mode.
     //
diff --git a/src/setup/display.c b/src/setup/display.c
index 79f799b4..3824122c 100644
--- a/src/setup/display.c
+++ b/src/setup/display.c
@@ -66,6 +66,7 @@ static window_size_t window_sizes_scaled[] =
 static char *video_driver = "";
 static char *window_position = "";
 static int aspect_ratio_correct = 1;
+static int integer_scaling = 0;
 static int force_software_renderer = 0;
 static int fullscreen = 1;
 static int fullscreen_width = 0, fullscreen_height = 0;
@@ -193,6 +194,9 @@ static void AdvancedDisplayConfig(TXT_UNCAST_ARG(widget),
     TXT_AddWidgets(window,
         ar_checkbox = TXT_NewCheckBox("Fix aspect ratio",
                                       &aspect_ratio_correct),
+#if SDL_VERSION_ATLEAST(2, 0, 5)
+        TXT_NewCheckBox("Integer scaling", &integer_scaling),
+#endif
         TXT_If(gamemission == heretic || gamemission == hexen
             || gamemission == strife,
             TXT_NewCheckBox("Graphical startup", &graphical_startup)),
@@ -249,6 +253,7 @@ void ConfigDisplay(void)
 void BindDisplayVariables(void)
 {
     M_BindIntVariable("aspect_ratio_correct",      &aspect_ratio_correct);
+    M_BindIntVariable("integer_scaling",           &integer_scaling);
     M_BindIntVariable("fullscreen",                &fullscreen);
     M_BindIntVariable("fullscreen_width",          &fullscreen_width);
     M_BindIntVariable("fullscreen_height",         &fullscreen_height);